US2008541A - Electric heating device - Google Patents

Description

July 16, 1935. D. T. BOYD ET AL 2,008,541

ELECTRIC HEATING DEVICE Filed Feb. 28, 1935 2 She'ets$heet l y 1935. D. T. BOYD ET AL ELECTRIC HEATING DEVICE Filed Feb. 28, 1933 2 Sheets-Sheet 2 dWa wVENTORS '7E/R ATTORNEY MEDIUM Patented 16, 1935 UNITED STATES PATENT OFFICE ELECTRIC HEATING DEVICE Drury T. Boyd, Bayside, and Jay R. Wohrley, Brooklyn, N. Y.

The present invention relates to electric heating devices.

It may be safely said there is no problem facing the owners and operators of electric utility properties at the present time of greater importance than the developing of means whereby their fixed capital investment may be employed more actively. Load factor is a measure of capital activity, and any scheme whereby the load factor can be increased will mean that additional load, and its consequent consumption, has been taken on without proportional increase in capital expenditures. Electric central stations require, for enlcient and economical operation, that the load on the station be as uniform as possible, and all peaks in power plant demand be avoided as much as possible. Any arrangement, therefore, which will definitely prevent the combined peak of certain items of installed current consuming equipment without interfering with the service for which they were intended is a step in the right direction. It is the main object of the invention to provide a construction and arrangement of certain electrical heating apparatus whereby these advantages, as indicated, may be realized.

The present invention is more particularly concerned with the combined electrically heated cooking ranges and electrically heated water heaters in the home, but may have other applications. It is desirous that combined electric range and electric water heater demand be prevented in the home and thus investment in service wires, meters, fuses and house wiring will be reduced. A better load factor on the electric distribution system and on the power plant will also result in further corresponding saving in capital expenditures by the power company. More domestic electric water heating load is needed by the utilities, and in almost every case it is being installed bya customer having previously installed (or who is simultaneously installing) an electric range. With no control of the current consumption of the electric water heater additional investment must be made to care for its demand also. But with control of its current consumption the range load investment will also care for the water heater load. The water heater control must be simple, safe, cheap and rugged and should not require extra effort or special care on the part of the housewife. To care for this, therefore, it is an object of the present invention to provide means which shall automatically prevent any considerable demand of current for water heating at the time cooking operations are being carried on; the proper control of the water heater involving no care on the part of the user of the range, but being automatically effected by the ordinary operation of the cooking unit control switches of the range.

The most practical and satisfactory domestic 5 electric water heater is that design having two units, or sets of heating elements; one unit or set being of relatively high wattage demand for quick recovery of hot water when needed, and a second unit or set being of relatively low wattage, which 10 smaller unit or set provides a high load factor base load for water heating. While each of these units, or sets of units, are operated independently of the other by separate thermostats, the current demand of the high wattage, or high de- 15 mand element or elements, is decidedly objectionable simultaneously with any range demand, so that in addition to being operated by a thermostat, the present invention provides a further means of automatically interrupting the circuit 20 to the high wattage water heater element or elements when any demand is made for current by the burner plates or oven of the range, and reestablishing this circuit when all the burner plates and oven are turned off.

A further object of the present invention is to provide a horizontal water heater tank which is efficient and which provides for the entire contents of the tank to be heated.

A further object of the present invention is so to utilize otherwise unoccupied space and unused floor space by placing the horizontal tank heater under the electric range.

A further object of the present invention is to provide efficient means for drawing off hot water 35 and simultaneous admittance of cold water, and for blowing off the heater without disturbance of the stored hot water.

Other and ancillary objects of the invention will appear hereinafter.

In the accompanying drawings which illustrate the invention- Fig. 1 is a top plan view of an electric range and a water heater (diagrammatically shown) embodying the invention, the electrical connec- 45 tions being diagrammatically shown;

Fig. 2 is a front elevation of the apparatus of Fig. 1, the switching mechanisms for controlling the cooking burners and oven, and the heater, being shown in perspective, and the electrical 50 connections being diagrammatically shown;

Fig. 3 is a perspective view, on an enlarged scale, and with the electrical connections diagrammatically shown, of switching mechanism for varying the heat generation of a cooking unit when in 2 use with its associated water heater circuit control switch; and

Fig. 4 is a'section on the line A-A of Fig. 2.

Referring to the drawings, the apparatus comprises the feeder conductors 2 and 3, there being a difference of potential of volts between the middle conductor 2 and either of the outside conductors I or 3, and there being a difierence of 220 volts between the outside conductors l and 3. The top of the range comprises the usual burner plates 4, 5 and 5 in connection with which are arranged the electric resistor heating elements 1, 8 and 9. (See Fig. 1.) At one end of this cooking top, as is usual in gas and electric ranges, is the oven in, having arranged in it the electric heating resistors H and I2. These resistors may be arranged in any suitable location or locations, but in the instance shown they are intended to represent that element II is located in the upper part of the oven chamber and element I2 is located in the lower part of the oven chamber.

Beneath the range top and the oven, as above referred to, is arranged the cylindrical water heating tank I3 with its axis extending horizontally. (See Fig. 2.) Extending longitudinally of the tank I3 .is the perforated water intake pipe I4 controlled by the valve l5 and connected with any suitable source of water supply. Near the top of the tank is a longitudinally extending perforated hot water draw-off pipe |6 leading through a pipe controlled by a valve H to the usual house hot water faucets. Also in the bottom of the tank is a perforated longitudinally extending blow-off pipe l8 through which the water may be drawn oil from the tank, the incoming coldwater through the pipe l4 serving to agitate any sediment in the bottom of the tank and enabling it to be readily drawn off through the pipe l8 without undue agitation of the stored hot water. The exit through the pipe I8 is normally closed by means of a valve l9.

Each of the heating resistors for each of the burner plates 4, 5 and 6 is divided into two sections. Corresponding to each of these resistors is a switching mechanism operated by a handle and indicator 20, 2| and 22-at the front of the range whereby the sections of the resistor may be connected in different relations to regulate the amount of heat developed at the resistor and, of course, the electricity consumed in developing such heat. Each of the switching mechanisms, connected to the switch handles 20, 2| and 22 respectively corresponding to each sectionalized resistor, is constructed in precisely the same way and operates in precisely the same way upon its resistor as the switching mechanisms connected to each of the other handles, so that a description of one such switching mechanism will apply to each.

Thus the handle 20 is fixed upon the shaft 23 rotatably mounted in the range and having insulated from, but fixed upon it, the conductor segments 24 and 25. In the position shown (see Fig. 3), the pointer of the handle 20 is toward the legend Oil and in this position the movable segment 24 is in contact with the stationary contact 26 only, while the segment 25 is in contact with the stationary contact 21 only. In this position neither of the sections 28 or 29 of the resistor 8 has a circuit completed through it so that no demand is made for current and no heat is generated in these resistor sections. If now the handle 20 be moved to the right (see Fig. 3) into the position where the handle pointer is directed to the legend "High, the three arms 35,

36 and 31 of the segment 24 will respectively engage with the stationary contacts 30, 26 and 3|, and the arms 32 and 33 of the segment 25 will respectively engage with the stationary contacts 34 and 21. In this position of the handle the resistor sections 28 and 29 will be connected in parallel across the 110 volt conductors 2 and 3, when a maximum current will be consumed, and therefore a maximum amount of heat will be generated at the resistor.

If now the pointer of the handle 28 be turned so as to be directed toward the legend Medium the arms 35 and 36 of the segment 24 will be respectively in engagement with the stationary contacts 26 and 3|, the arm 31 being out of engagement, whilethe arms 33 and 38 of the segment 25 will be respectively in engagement with the stationary contacts 34 and 21, the arm 32, being unconnected. The resistor section 29 will then be connected across the 110 volt conductors 2 and 3; no circuit being completed through the resistor section 28.

If now the pointer of the handle 28 be moved to indicate the legend Low, the contact segment arms 35 and 31 will respectively engage with the stationary contacts 3| and 30, the arm 36 being disconnected, while the arms 33 and 38 of the segment 35 will be respectively in engagement with the stationary contacts 39 and 34, the arm 32 being disconnected. The resistor sections 28 and 29 will then be connected in series between the 110 volt conductors 2 and 3.

The oven resistor H is divided into two sections 40 and 4|, while the oven resistor I2 is divided into the two sections 42 and 43. The sections 4| and 43 are permanently connected in parallel so as to be controllable as one unit, and serve to divide the heat generated between the top and bottom of the oven. Also, with similar effect, the sections 48 and 42 are permanently connectedin parallel. These oven resistors are controlled by a switch handle 44 the same as any one of the switch handles 20, 2| or 22 and similarly connected with a switch mechanism which is the same as that shown in Fig. 3 as has just been described. The turning of the switch handle 44 into the positions High, Medium and Low has the eifect of connecting the oven units consisting of sections 4| and 43 in parallel and the sections 48 and 42 in parallel, into the various relations of parallel of the sections for the High, connecting but one of the sections for the Medium, and the sections in series for the Low, in a manner precisely analogous to that described in connection with the resistor 8 and with special reference to Fig. 3.

To heat the water in the water tank |3 an electric resistor heating element 45 is mounted near one end of the tank and between a vertical baffle tween the baflie plate and the top of the tank,

while at the bottom of the baflle plate and between it and the bottom of the tank is the opening 62.

Similarly there are openings 63 and 64 at the top and bottom of the baffle plate 48. It will be noted Between the baflie plates 46 and 48 and the respective tank ends are located the resistor heating elements 65 and 66. These elements, it will be observed, are located in the lower part of the tank, it will be seen that they are below the resistors and 41 and below the baflie plates 49 and 50. The resistors 65 and 66 are connected in parallel across the 220 volt conductors l and 3 and are controlled by a thermostat 81 which is operated by the heat of the water below the baflie plate opening 60 and about midway between the ends of the tank, such thermostat operating to break the circuit of the heating elements 65 and 66 when the water temperature at that point equals a certain desired value. The heater elements 45 and 41 are connected in parallel and are adapted to be connected across the 220 volt supply conductors I and 3 through the thermostat 68 in a manner which will now be described.

One of the conductors l is connected directly to the thermostat 68. Connection from the thermostat to the otherieeder 3 is made through the pairs of contacts 69, 10, H and 12, there being a pair of contacts corresponding to each of the handles 20, 2 I, 22 and 44; there being a movable contact blade on the switch shaft attached to each handle adapted to connect its pair of contacts when the switch is in a certain position. The mechanism is the same for each of the handles and its pair of contacts and so will be described for one of them only, such description applying to each.

Referring to Fig. 3, the shaft 23 has fixed upon, and insulated from it, a connecting segment I3. In the position of the switch shown, namely with the switch in the off position as regards the heating resistor for the corresponding burner plate or oven, the segment 13 connects the contacts 72, but in all other positions of the handle (that is whenever any current is being supplied to the burner plate or oven resistors) the segment I3 will be in such position that it will not connect the contacts 72. It will be seen that the pairs of contacts 12, H, 10 and 69 are connected in series so that it is necessary that all of them be closed in order to establishcircuit to the water heater thermostat 68 and thence to resistors 45 and 41 (see Figures 1 and 2). It is therefore necessary that all of the handles 20, 2|, 22 and 44, be in their off positions (and no current being supplied to the burner plates nor the oven) in order to establish circuit to the water heater thermostat '68 and thence to resistors 45 and 41. If any one of the handles 20, 2| 22 or 44 is turned into position such that current is supplied to a burner plate or oven no circuit will be made to the water heater thermostat '68 and thence to resistors 45 and 47.

It will be observed that the thermostat 68 is located directly above the opening 60 between the horizontal baiiie plates and substantially midway between the ends of the tank and will also disconnect the circuit of the heating elements 45 and 41 when the temperatureof the water at that point equals a certain desired value.

The resistors 65 and 66 are of relatively low electric current consumption and heat development, operating to heat the water by application of heat over a considerable period of time. On account of the relatively low wattage demand of these elements they are connected direct to the 220 volt conductors independently of the burner plate and oven resistors of the range and remain in operation at all times except when disconnected by the operation of the thermostat 61.

The heating resistors 45 and 41 are of relatively high current consumption and rapid generation of heat; of higher demand than the elements 65 and 66.. Accordingly, to prevent a combined range and high wattage water heater element peak, the circuit supplying elements 45 and 41 through thermostat 68 should be interrupted whenever there is a demand for current for range burner plate or oven purposes. The control arrangements have therefore been made as described, whereby the circuit supplying elements 45 and 41 is automatically interrupted, regardless 01' whether thermostat 68 is open or closed whenever current demand for burner plates or oven is made.

The result of such connection of circuits to the electric water heater is that the elements 65 and 66, being of relatively low wattage are permanently connected to the power supply and operated only by thermostat 61, and will provide a high load factor base load for water heating, having also available elements 45 and 41 of relatively high wattage for quick recovery of hot water; however, the current demand of elements 45 and 47 is objectionable simultaneously with any range demand, so that in addition to being operated by thermostat 58 there is provided a further means of automatically disconnecting that circuit when any demand is made for current by the burner plates or oven of the range, and reestablishing it when all the burner plates and oven are turned on.

It will be observed from the foregoing that the resistors 7, 8 and 9 of the cooking plates 4, 5 and 6 may be controlled in the usual way to regulate the amount of heat generated by them respectively by means of the usual service switches 20, 2i and 22 respectively which are directly connected, that is without the interposition of any other switches, with the resistors. Also that the oven heating resistors may be controlled in the same way by the switch 44.

t will be further seen that the quick recovery (high wattage demand) water heating resistors 45 and 4'! have their circuit made through the switches 69, 10, H and 12 in series, so that if any of the cooking plate or oven control switches are out of the ofi position, the circuit to the quick recovery resistors is broken. In other words the circuit to the high wattage demand elements is opened by the turning on of any of the cooking or oven heaters and with no attention on the part of the operator, the cutting out of these elements being automatic upon the simple operation of any .of the cooking or oven heater control switches. It will be seen that it is necessary, in order to establish circuit of the resistors 45 and 41, that all of the switches 69, 70, H and I2 shall be closed which can only take place when all of the cooking and oven control switches are in their off positions. It will further be observed that the low wattage demand elements 65 and 66 are permanently connected in circuit and are controlled as to current supply by thermostat 61.

The present invention is not limited as to voltages and phase of circuits. Also, while the sketches show by the electric circuits the range element switches to be the two wire, three heat type, this was so drawn for simplicity, and the electric water heater circuit modification as indicated will apply equally well to the load balancing type of electric range switch.

While the invention has been illustrated in what is considered its best application it may have other embodiments without departing from its spirit and is not limited to the structures shown in the drawings.

What we claim is: r

1. The combination with a plurality oielectric heating resistors, of a source of electrical supply for said resistors, switching means corresponding to each of said resistors and controlling the same, another electric heating resistor and a plurality of switching means each mechanically operatively connected with one of the aforesaid switching means; for controlling the last mentioned resistor, the last mentioned switching means'being in series in the circuit of the last mentioned resistor.

2. In a combined electric cooking range and water heater, the combination with a plurality of cooking units each having an electrical heating resistor, of a source of electric supply, switching means corresponding to each of said cooking resistors and controlling the same, a water tank, an electric resistor for heating the water therein and a plurality of switching means, each mechanically operatively connected with one of the said cooking resistor switching means, for controlling the current supply to the water heater resistor, said plurality of switching means for controlling the current supply to the water heater resistor being connected in series in the circuit of said water heater resistor.

3. In an electric cooking range, the combination with a plurality of cooking units each having an electric heat resistor, of a source of electrical supply for said resistors, a manually operated switch corresponding to each of said resistors and controlling the same and an additional switch corresponding to each of' the aforesaid switches and having a manually operating means in common therewith and means connecting said additional switches in series.

4. In an electric cooking range, the combination with a plurality of cooking units each having an electric heat resistor, of a source of electrical supply for said resistors, a manually operated switch corresponding to each of said resistors and controlling the same and an additional switch corresponding to each of the aforesaid switches and having a manually operating means in common therewith, said additional switches being connected in series in the circuit of a water heater resistor.

DRURY T. BOYD. JAY R. WOHRLEY.

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